Well, all things considered I think that you can try Famotidine, it's inexpensive.
It won't do too much harm if you try small dose for a 2 - 3 days, it
might help.
The problem is that I totally forgot how to dose...and what frequency. Sorry.
You 'll need to talk to others with experience with Fam, there used to be a lot of people here who used F daily, you should get recommendations.
I am not very current and I do not know who uses it now, and whose cats display similar symptoms. So, do not know whom to tag for you.
Edit your title - click on question mark icon at the left of the title line and then type something more specific - like "Help with throwing up/ Acid Reducer dose". The question mark prefix will attract more eyes.
Hopefully, the situation will resolve with easy/ available things such as the Fam.
Have you heard of Care Credit?
It is line of credit for vet-, med-, or some other services, that you do not have to pay any interests on if paid off in 6 month. It is a savior for so many on here! A lot of hospitals and private vet clinic accept it now - and I hear that t he number of services participation in accepting CC is growing. In case you'll need to run a bloodwork one day. And they do approve everyone, lol.
I may be wrong but I cannot remember hearing/ reading here that a cat with a flare of P-titis was having good appy and ate well

. If it was a flare up you , likely, would
not be seeing good eating. I hope I am not wrong, and you can relax about p-titis. It is painful, and requires pain killers at least for a while.
As for the cleaning detergent - I used to do Pine Sole on everything

. Turns out to be very toxic for any being.
Now it 's been replaced by 1:1 water/white vinegar. Works just fine, the remaining odor is very slight and short lived, does not seem to bother Ducia at all.